The University of Louisville is promoting structural biology and cancer research as part of its core mission. Under the aegis of the JG Brown Cancer Center and the Department of Chemistry, a number of core facilities and major collaborative programs are being established. This currently includes NMR spectroscopy, X-ray crystallography, Molecular Modeling, and protein expression. To enable the functional analysis of macromolecules and their interactions in the solution state, we are now building a biophysics core to be headed by a senior scientist. We have identified analytical ultracentrifugation as an integral component of this core. An essential part of any functional analysis is the determination of the physical state of the isolated components (including molecular weight, shape, hydration and homogeneity), as well as measuring the stoichiometry of the complexes and the interaction strength. This is difficult to achieve by other nonequilibrium methods because of the dependent of the parameters on both shape and size. The analytical ultracentrifuge is one of the few techniques that can independently and rigorously determine mass of a functional component in a non-denaturing state in solution, as well as provide information about homogeneity and frictional properties. Furthermore, it is generally necessary to know the stoichiometry, and preferably the symmetry, of an oligomer or complex before a complete NMR structure determination can be contemplated. The analytical ultracentrifuge is an ideal shared instrument, as it can readily accommodate several research groups whose primary methodologies are not in the hydrodynamics of macromolecules, but who need the specific data it provides in order to further their research and solve problems that cannot be tackled by other techniques. Hydrodynamic analysis of macromolecules can be seen as an integral part of the overall biophysics program at the Cancer Center. The combination of structural and biophysical techniques is central to understanding regulatory processes inside cells, and for providing the basic information about basic drug targets during the drug discovery and development process. There are numerous NIH-funded investigators who need access to this instrumentation, and who would be major users. There are many other groups who will need less frequent access. All of the researchers are actively involved in protein expression and analysis of complex interactions related to disease states.